How would one go about designing a comedic and metaphysical Inform 7 game like The Stanley Parable with an omniscient narrator that emphasizes the use of choice, seemingly random variability, and multiple endings that change between each playthrough?

Ryan Veeder wrote a game called Craverly Heights whose source is both available and nicely organized.

The game has a script that you can either follow or go off of. Players can rebel completely or even purposely screw up the script. If you do crazy actions, the pc makes comments like “I don’t know why I’m doing this.”

It’s not exactly what you’re looking for, but it could give you some ideas.